Ivan Petrovitch Pavlov at 85, speaking at the XV International Physiological Congress, Leningrad, 1935

Excerpts from Lectures on Conditioned Reflexes, Volume II: Conditioned Reflexes and Psychiatry

Ivan Petrovitch Pavlov



(Reply to Schilder’s Criticism – Neuroses and the Physiological Analyses.


IN THE Journal of Nervous and Mental Diseases, volume 70, there is printed an article by Dr. P. Schilder, entitled “The Somatic Basis of the Neurosis,” in which the author recognises that what we, I and my collaborators, call neuroses in our experimental animals (dogs) “are formed of the manifestations of neuroses.” Such recognition from a competent source is, of course, very valuable for us. But I most emphatically object to what the author further says concerning the comparative study of these neuroses in man and in animals. He says, “The important experiments of Pavlov and his pupils on neuroses can be understood only if we look upon them in the light of our experiences in the neuroses. We cannot interpret the neurosis by means of the conditioned reflex, but by means of the psychic mechanism we have studied in the neurosis we can well explain what occurs in the conditioned reflex.”

What is the meaning of the term “interpretation” or “understanding” of the phenomenon? The reduction of the more complex to the more elemental is a simple thing. Consequently the human neuroses should be explained, understood, i.e., analysed, by the help of the animal neuroses, as naturally the more simple, and not by the reverse procedure.

In man it is necessary first to determine exactly wherein lies the deviation from the normal. But the behaviour of the normal is exceedingly varied in different persons. Then one should consider together with the patient, or independently of him, or even against his resistance, among the chaos of affairs vital to him, those conditions that have acted immediately or gradually and with which perhaps the origin of the illness may be justifiably linked. Further, one must know why these conditions and difficulties produced such a result in our patient, when they are without influence on other people. And why does this lead to a certain complex in one patient and to an entirely different one in another patient. I am taking only the most important group of questions, omitting the details. Are there always entirely satisfactory answers to all these questions?

But this is only a part of the matter if one attempts a complete and final analysis. Of course the deviation in behaviour of our patient comes from a change in his nervous system. Who can now deny that? Therefore it is necessary to answer this question: how and why do there arise in the given case changes in the normal processes of the nervous system? Are not these real prerequisites? And where are they all satisfied? With what does one deal in the dog?

First of all, one sees that neuroses are possible to obtain and without difficulty, if only one has an animal in whose makeup there is not a proper balance between its fundamental reactions of nervous activity – as yet not further analysed physiologically – that is, between the excitatory and inhibitory processes.

Further, with such an experimental animal it is definitely known that this insufficient balance, peculiar to the make-up of the particular animal, finally breaks down under certain fundamental conditions. This happens mainly under three conditions, three circumstances. Either extremely strong stimuli in the nature of conditioned stimuli are used in the place of those that are only weak or moderately strong and which ordinarily determine the animal’s activity; i.e., its excitatory processes are overstrained. Or the animal is required to exert a very strong or a very protracted inhibition; i.e., its inhibitory processes are overstrained. Or, finally, a conflict between both these processes is produced; i.e., conditioned positive and negative stimuli are applied one right after the other. In all these cases with the proper animal there develops a chronic disturbance of the higher nervous activity, a neurosis. The excitatory type loses almost completely its ability for any inhibition and generally becomes unusually excited; the inhibitory type, though hungry, refuses even to eat under the influence of the conditioned stimuli and generally becomes exceedingly ill at ease and also passive with the least change of its surrounding environment.

One can conceive in all likelihood that, if these dogs which have become ill could look back and tell what they had experienced on that occasion, they would not add a single thing to that which one would conjecture about their condition. All would declare that on every one of the occasions mentioned they were put through a difficult test, a hard situation. Some would report that they felt frequently unable to refrain from doing that which was forbidden and then they felt punished for doing it in one way or another, while others would say that they were totally, or just passively, unable to do what they usually had to do.

And so, what my associates and I have found with our animals are elemental physiologic phenomena – the frontier of physiologic analysis (in the present state of knowledge). At the same time it is the prime and most fundamental basis of human neurosis and serves as its true interpretation and understanding.

Hence in the case of man, under the complications of his existence and with his many different reactions to it, when it comes to analysis and to the ultimate aim of curing him, one always has to face the very difficult question: What circumstances in his life are excessively strong for the nervous system in question, where and when has he encountered a conflict intolerable for him, requirements that he become active and requirements that he hold himself back? How in the opinion of Dr. Schilder could the innumerable subjective experiences of the neurotic patient under the extreme complexity of human higher nervous activity, as compared with dogs, give anything useful in the way of an explanation of the elementary neuroses of animals. when those experiences are only different variations of one and the same physiologic process, so clearly seen in dogs? Of course, for the final physiologic analysis of the problem of neuroses and psychoses there remain a number of unsolved questions. Is it possible to produce neuroses in cases of well balanced nervous systems? Is the initial unbalance of the nervous system a primary phenomenon: i.e., an innate property of the nervous tissue itself, or a secondary one depending on some innate peculiarity of other systems of the organism apart from the nervous system? Do there not exist along with the innate properties of the nervous system also other conditions in the organism which determine this or that degree of normal function of that system? I am busy at the present time with some of these questions and already have material for their decision.

It stands to reason that, apart from these special questions which concern the general problem of disorders of normal nervous activity, there remains before the physiologist the question relating to the physicochemical mechanism of these very elemental nervous processes: of excitation and inhibition, of their reciprocal relations and tensions, and of excessive strains on them.

Ivan Petrovitch Pavlov, Lectures on Conditioned Reflexes, Volume II: Conditioned Reflexes and Psychiatry, translated and edited by W. Horsley Gantt, Lawrence & Wishart Ltd., London 1941.

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